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BKDR_LIFTOH.AD
Aliases: Downloader.Liftoh (Symantec); Win32/Injector.AORA (ESET-NOD32)
Malware type: Backdoor
Destructive: No
Platform: Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Encrypted: Yes
In the wild: Yes

Overview


Infection Channel: Dropped by other malware, Downloaded from the Internet

This malware is involved in a ZBOT spam campaign that targeted British users. Once the malicious attachment is opened, it inevitable leads to the download of ZBOT malware into the affected system.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system.

Technical Details


File size: 162,816 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 15 Oct 2013
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor drops the following copies of itself into the affected system:

  • %All Users Profile%\Application Data\{random letters}sacfsfdsf.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random letters}sacfsfdsf = ""%All Users Profile%\Application Data\{random letters}sacfsfdsf.exe""

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\{random letters}sacfsfdsf

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\{random letters}sacfsfdsf
CurrentPath111 = "%All Users Profile%\Application Data\{random letters}sacfsfdsf.exe"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download configuration file
  • Update copy of itself
  • Download and Execute possibly malicious files
  • Inject arbitrary routines to a running process

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • 404.{BLOCKED}dns.com/feed404/feed.php via port 80

NOTES:
As of this writing, this backdoor receives commands from its C&C server to download files from the following URLs:

  • feedweb.{BLOCKED}dn.net//feedswebz/html/myupdates.exe
It saves the file it downloads using the following name:
  • %All Users Profile%\Application Data\{random file name}.exe - detected as TROJ_AGENT.BGTI

Solution


Minimum scan engine: 9.300
First VSAPI Pattern File: 10.342.04
First VSAPI Pattern Release Date: 15 Oct 2013
VSAPI OPR Pattern Version: 10.349.00
VSAPI OPR Pattern Release Date: 16 Oct 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove the malware/grayware file that dropped/downloaded BKDR_LIFTOH.AD

Step 3

Restart in Safe Mode

[ Learn more ]

Step 4

Delete this registry key

[ Learn more ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.


  • In HKEY_CURRENT_USER\Software
    • {random letters}sacfsfdsf

Step 5

Delete this registry value

[ Learn more ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.


  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random letters}sacfsfdsf" = ""%All Users Profile%\Application Data\{random letters}sacfsfdsf.exe""

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_LIFTOH.AD. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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Analysis By: Alvin Bacani

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